Declining Exponential Approximation of Life Expectancy

The declining exponential approximation of life expectancy (DEALE) is a model that simplifies the problem of handling life expectancy calculations in clinical decision analyses. During the early years of clinical decision analysis, much of the focus was on tree construction and probability estimation. Utility or outcome measures were less of a focus; measures such as “percent chance of cure” or “5-year survival” were commonly used in lieu of life expectancy values. In large part, this was because the clinical literature reported results that way. Combining medical risks to estimate survival was rarely done. As decision modelers focused on chronic diseases over short-term [Page 364]problems, the need arose to model life expectancy for healthy persons and those battling disease.